End effector assembly

ABSTRACT

Generally, an end effector assembly for a substrate transfer robot is provided. In one embodiment, an end effector assembly for supporting a quadrilateral substrate during substrate transfer includes an end effector having an inner edge support disposed on a first end and a first outer edge support disposed on a distal end. The first end of the end effector is adapted for coupling to a robot linkage. The first inner edge support has a face that is oriented parallel to and facing the face of the first outer edge support. This configuration of edge supports captures the substrate to the end effector thereby minimizing substrate slippage during transfer. In another embodiment, lateral guides may be utilized to further enhance capturing the substrate along the edges of the substrate open between the inner and outer edge supports.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] Embodiments of the invention relate to an end effector assemblyfor supporting substrates.

[0003] 2. Background of the Related Art

[0004] Thin film transistors (TFTs) are conventionally made on largeglass substrates or plates for use in monitors, flat panel displays,solar cells, personal digital assistants (PDAs), cell phones and thelike. TFTs are made in a cluster tool by sequential deposition ofvarious films including amorphous silicon, doped and undoped siliconoxides, silicon nitride and the like in vacuum chambers typicallydisposed around a central transfer chamber. Production of good qualitypolysilicon precursor films utilized in these structures requires thatthe hydrogen content of the film be controlled below about 1 percent. Inorder to achieve this low hydrogen content, post deposition heattreatment of the film at temperatures of about 550 degrees Celsius isrequired.

[0005] Accordingly, robots utilized to move substrates in these clustertools must have end effectors designed to withstand these hightemperatures. Generally, conventional transfer robots are not suited foroperation at such high temperatures. Particularly, the end effectors ofvacuum robots utilized in flat panel processing systems typicallyinclude one or more rubber friction pads upon which the substrates rest.The friction pads generally prevent the substrate from sliding relativeto the end effector as the robot transfers the substrate from chamber tochamber. Several high temperature rubber compounds are available but aretypically limited to a maximum operating temperature of about 320degrees Celsius, significantly lower than the 550 degrees Celsiusdesired in polysilicon heat treating processes. When the end effector ofthe robot is exposed to high temperature for more than ten seconds,these conventional rubber pads typically melt and stick to thesubstrate. The melted rubber stuck to the backside of the substrate isundesirable both due to potential contamination and subsequentprocessing issues. Moreover, once the rubber pad is removed from the endeffector, scratching of the backside of the substrate by the endeffector may occur which may lead to particulate generation andsubstrate damage or breakage. Furthermore, if the rubber pad melts,replacement of the pad is difficult.

[0006] Therefore, there is a need for an end effector suitable for useat elevated temperatures.

SUMMARY OF THE INVENTION

[0007] In one aspect of the invention, an end effector assembly for asubstrate transfer robot is provided. Generally, an end effectorassembly for a substrate transfer robot is provided. In one embodiment,an end effector assembly for supporting a quadrilateral substrate duringsubstrate transfer includes an end effector having an inner edge supportdisposed on a first end and a first outer edge support disposed on adistal end. The first end of the end effector is adapted for coupling toa robot linkage. The first inner edge support has a face that isoriented parallel to and facing the face of the first outer edgesupport. This configuration of edge supports captures the substrate tothe end effector thereby minimizing substrate slippage during transfer.In another embodiment, lateral guides may be utilized to further enhancecapturing the substrate along the edges of the substrate open betweenthe inner and outer edge supports.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A more particular description of the invention, brieflysummarized above, may be had by reference to the embodiments thereofthat are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only typical embodimentsof this invention and are therefore not to be considered limiting of itsscope, for the invention may admit to other equally effectiveembodiments.

[0009]FIG. 1 is a plan view of one embodiment of a processing system;

[0010]FIG. 2 is a plan view of one embodiment of a transfer robot havinga plurality of substrate supports disposed on an end effector;

[0011]FIG. 3 is an exploded view of one embodiment an edge support ofFIG. 2;

[0012]FIG. 4 is a sectional view of the edge support of FIG. 2 takenalong section line 4-4;

[0013]FIG. 5 is an exploded view of one embodiment of a spacer assemblyof FIG. 2;

[0014]FIG. 6 is a partial exploded view of the spacer assembly of FIG. 5having alternative embodiment of a lateral guide;

[0015]FIG. 7 is a perspective view of another embodiment of a spacerassembly;

[0016]FIG. 8 is a sectional view of one embodiment of a center supportof FIG. 2 taken along section line 9-9; and

[0017] FIGS. 9A-F depict perspective top views of various embodiments ofa patterned support surface.

[0018] To facilitate understanding, identical reference numerals havebeen used, wherever possible, to designate identical elements that arecommon to the figures.

DETAILED DESCRIPTION

[0019]FIG. 1 depicts a schematic layout of a cluster tool 100. Thecluster tool 100 generally comprises a transfer chamber 102 having afirst transfer robot 104 disposed therein. The transfer chamber 102 issurrounded by a plurality of processing chambers 106, a thermalprocessing chamber 108 and at least one load lock chamber 110. The loadlock chambers 110, two of which are depicted in FIG. 1, are generallycoupled between the transfer chamber 102 and a factory interface 112.One cluster tool that may be adapted to benefit from the invention isavailable from AKT, Inc., a wholly-owned division of Applied Materials,Inc., located in Santa Clara, Calif.

[0020] The factory interface 112 generally includes a second transferrobot 114 that transfers substrates 116 between the load locks 110 and aplurality of wafer storage cassettes 118 coupled to or disposed withinthe factory interface 112. The second transfer robot 114 may beconfigured similar to the first transfer robot 104 described below. Thefactory interface 112 is generally maintained at or near atmosphericpressure. The second transfer robot 114 is typically configured to movelaterally within the factory interface 112 so substrates 116 may betransferred between the load locks 110 and the cassettes 118 withminimal handling and time expenditure.

[0021] Each load lock chamber 110 generally allows for the substrate 116to be transferred between a sub-atmospheric environment maintained inthe transfer chamber 102 and the atmospheric environment of the factoryinterface 112 without loss of vacuum from the transfer chamber 102. Theload lock chambers 110 may be configured to transfer more than onesubstrate 116 at a time and may additionally heat or cool thesubstrates. One load lock chamber that may be used to advantage isdescribed in U.S. patent Ser. No. 09/464,362, filed Dec. 15, 1999(attorney docket no. 3790), which is hereby incorporated by reference inits entirety.

[0022] The transfer chamber 102 is typically fabricated from a singlemass of material such as aluminum to minimize vacuum leaks. The transferchamber 102 includes a plurality of passages 122 disposed in the wallsof the chamber 102 to allow transfer of substrates therethrough. Eachpassage 122 is selectively sealed by an isolation valve 120. Oneisolation valve that may be used to advantage is described in U.S. Pat.No. 6,079,693, issued Jun. 27, 2000 to Ettinger et al., which is herebyincorporated by reference in its entirety.

[0023] The processing chambers 106 are generally disposed about theperimeter of the transfer chamber 102. The processing chambers 106 maybe configured to include etch chambers, deposition chambers and/or otherchambers suitable for fabricating a desired structure or device on asubstrate.

[0024] The thermal processing chamber 108 generally heats or thermallytreats one or more substrates 116 disposed therein. The thermalprocessing chamber 108 generally includes at least one substrate support(not shown) adapted to support one or more substrates 116 within thethermal processing chamber 108. The thermal processing chamber 108additionally includes a thermal control system (also not shown), whichmay includes lamps, resistive heaters, fluid conduits and the like, touniformly heat substrates to about 550 degrees Celsius. One thermalprocessing chamber that may be used to advantage is described in U.S.patent application Ser. No. 10/025,152, filed Dec. 18, 2001, by Q.Shang, which is hereby incorporated by reference in its entirety.

[0025] The first transfer robot 104 is centrally disposed in thetransfer chamber 102. Generally, the first transfer robot 104 isconfigured to transfer substrates 116 between the chambers 106, 108, 110surrounding the transfer chamber 102. The first transfer robot 104 istypically configured to handle single substrates, however, robotsconfigured to handle multiple substrates may also be utilized.

[0026]FIG. 2 is a plan view of one embodiment of a first transfer robot104. The first transfer robot 104 generally comprises a robot body 202that is coupled by a linkage 204 to an end effector 206 that supports asubstrate 116 (shown in phantom) thereon. The end effector 206 may beconfigured to retain the substrate thereon in a desired manner, such as,for example, friction, electrostatically, vacuum chucking, clamping,edge gripping and the like. In one embodiment, the linkage 204 has afrog-leg configuration. Other configurations for the linkage 204, forexample, a polar configuration may be alternatively utilized. Oneexample of a polar robot that may benefit from the invention isdescribed in U.S. patent Ser. No. 09/547,189, filed Apr. 11, 2000 byEttinger et al., which is incorporated herein in its entirety.

[0027] The linkage 204 generally includes two wings 208 coupled byelbows 210 to two arms 212. Each wing 208 is additionally coupled to anelectric motor (not shown) concentrically stacked within the robot body202. Each arm 212 is coupled by a bushing 214 to a wrist 216. The wrist216 couples the linkage 204 to the end effector 206. Typically, thelinkage 204 is fabricated from aluminum, however, materials havingsufficient strength and smaller coefficients of thermal expansion, forexample, titanium, stainless steel, metal matrix or a ceramic such astitanium-doped alumina, may also be utilized.

[0028] Each wing 208 is independently controlled by one of theconcentrically stacked motors. When the motors rotate in the samedirection, the end, effector 206 is rotated at an angle ω about thecenterline 218 of the robot body 202 at a constant radius. When both ofthe motors are rotated in opposite directions, the linkage 204accordingly expands or contracts, thus moving the end effector 206radially inward or outward along an imaginary datum line 220 passingthrough the centerline 218 of the first transfer robot 104. The firsttransfer robot 104 is also capable of a hybrid motion resulting fromcombining the radial and rotational motions simultaneously.

[0029] The end effector 206 is typically fabricated from aluminum,quartz, carbon, metal matrix or ceramic and configured to support asubstrate with minimal sag. In the embodiment depicted in FIG. 2, theend effector 206 is ceramic and includes a base 228, a first member 230and a second member 232. Each of the first and second members 230, 232is coupled to the base 228 at a first end 250 and extends therefrom to adistal end 252. The base 228 is coupled to the wrist 216 of the firsttransfer robot 104. The first member 230 and the second member 232 aregenerally disposed in spaced-apart relation typically mirrored about thedatum line 220 that bisects the base 228. The length and spacing betweenthe first member 230 and the second member 232 is selected to adequatelysupport the substrate during transfer while minimizing substrate sag. Atleast one connecting member 234 is coupled between the first member 230and second member 232 to provide additional structural rigidity to theend effector 206.

[0030] The end effector 206 generally includes a plurality of substratesupports disposed thereon to support a substrate in a spaced-apartrelation to the end effector during substrate transfer. In theembodiment depicted in FIG. 2, the end effector 206 has pair of opposinginner and outer edge supports 224A, 224B and a center support 226disposed on each of the first and second members 230, 232 for a total ofsix (6) substrate supports. The inner and outer edge supports 224A, 224Bhave parallel opposing faces that capture the substrate 116 therebetweento substantially prevent movement of the substrate 116 relative to theend effector 206 during substrate transfer, thereby facilitatingincreased robot rotational speed and corresponding substrate throughput.Two lateral guides 222 may be utilized to further augment substrateretention in a direction parallel to the edge supports 224A, 224B.

[0031] The outer edge supports 224A from each opposing pair are coupledto the distal end 252 of the end effector 206. The opposing inner edgesupport 224B is coupled to the first end 250 of the end effector 206.The edge supports 224B may alternatively be part of a spacer assembly260 coupled to the first end 250 of the end effector 206 utilized toposition the lateral guide 222.

[0032]FIG. 3 is an exploded view of one embodiment of the outer edgesupport 224A of FIG. 2. The inner edge support 224B may be similarlyconfigured. The outer edge support 224A is fabricated from a materialsuitable for high temperature use that does not mar, scratch orotherwise contaminate the substrate 116. In one embodiment, the outeredge support 224A is fabricated from a thermoplastic material having amelting point greater than about 500 degrees Celsius, thus facilitatinghandling of high temperature substrates without melting or sticking ofthe support to the substrate. The outer edge support 224A may also havehardness less than about 150 Rockwell M. Examples of suitablethermoplastics include high performance semi-crystalline thermoplastics,polybenzimidazole and polyetheretherketone, among others. Other suitablematerials include stainless steel and ceramic.

[0033] The outer edge support 224A includes a top surface 302 having aplurality of steps 308 and an opposing bottom surface 304. The bottomsurface 304 is disposed on an upper surface 330 of the end effector 206.Each step 308 includes a support surface 310 and a retaining surface312. The support surface 310 is configured to support the substrate 116thereon and is typically oriented in a plane parallel to the uppersurface 330 of the first member 230. The support surface 310 may also bepatterned, textured, embossed, dimpled, slotted or otherwise include aplurality of surface features which reduce the contact area with thesubstrate 116 to minimize heat transfer therebetween. Some examples ofpatterned support surfaces are described further below with reference toFIGS. 9A-F.

[0034] The retaining surfaces 312 are generally planar and extendvertically from the support surfaces 310. Alternatively, the retainingsurfaces 312 may be flared away from a first side 306 of the outer edgesupport 224A to provide an entrance angle that facilitates seating ofthe substrate 116 on the support surface 310. The retaining surface 312is oriented parallel to and facing a retaining surface of the opposinginner edge support 224B disposed on the first member 230 to capture andretain the substrate 116 therebetween as depicted in FIG. 2.

[0035] Referring additionally to FIG. 4, the outer edge support 224Aincludes a plurality of mounting holes 318. A fastener 340 is disposedthrough each mounting hole 318 and a slot 332 formed in the first member230 and is threaded into a nut 342 to secure the outer edge spacer 224Ato the end effector 206. The slots 332 are oriented substantiallyperpendicular to the plane of the retaining surface 312 and parallel tothe datum line 220 to facilitate adjustment of the outer edge support224A on the end effector 206. The slots 332 allow the distance betweenopposing edge supports 224A, 224B to be set so that edges 404 (one isshown in FIG. 4) of the substrate 116 are captured between the retainingsurfaces 312 of the steps 308 to prevent movement of the substrate 116during substrate transfer. Alternatively, the mounting hole 318 may beelongated (i.e., slotted) to facilitate adjustment of the outer edgespacer 224A.

[0036] In one embodiment, a recess 402 is formed in a bottom surface 406of the first member 230 to allow the nut 304 to be disposed on thedistal end of the fastener 340 below the bottom surface 406 of the endeffector 206. The recess 402 is configured with adequate clearance spacefor the nut 304 to move laterally as the fastener 340 is moved betweenends of the slot 332.

[0037]FIG. 5 is an exploded view of one embodiment of a spacer assembly260 coupled to the end effector 206. The spacer assembly 260 includes anoutrigger 502 and at least the lateral guide 222. The outrigger 502 hasa first end 506 and a second end 508. A mounting pad 504 is attached tothe second end 508 of the outrigger 502 and has the lateral guide 222attached thereto. The lateral guide 222 may be coupled to the mountingpad 504 by a variety of methods, including adhering, bonding, riveting,staking, fastening and the like. The outrigger 502 is configured toposition the lateral guide 222 slightly outward of a lateral edge 540(e.g., edge of the substrate 116 perpendicular to the edge 404) therebypreventing the substrate 116 from moving laterally relative to the datumline 220 while being rotated by the robot.

[0038] The outrigger 502 is typically fabricated from the same materialutilized for the end effector 206 and is coupled by first end 506 to thefirst end 250 of the end effector 206. In one embodiment, the first end506 of the outrigger 502 is disposed in a channel 510 formed in the endeffector 206. The channel 510 includes a plurality of slots 512 thataccept fasteners 514 passing through holes 516 formed through the firstend 506 of the outriggers 502. A nut 518 is mated with each fastener 514to secure the outrigger 502 to the end effector 306. The slots 512 areoriented substantially perpendicular to the datum line 220 (shown forreference in FIG. 5) so that the position of the lateral guide 222coupled to the outrigger 506 may be adjusted to accommodate a predefinedsize substrate 116 without undue clearance for tolerance stacking.Alternatively, the holes 516 may be elongated (i.e., slotted) tofacilitate adjustment of the outriggers 502.

[0039] In one embodiment, the inner edge support 224B may be coupled tothe mounting pad 504 adjacent the lateral guide 222. The inner edgesupport 224B is generally configured to mirror the outer edge support224A and may also be adjustable in a direction parallel to the datumline 220 so that the substrate 116 may be suitable capturedtherebetween.

[0040] The lateral guide 222 may be fixed relative to the mounting pad504 or adjustable in a direction perpendicular to the datum line 220.The lateral guide 222 may be coupled to the mounting pad 504 by staking,bonding, riveting, adhering, clamping, screwing, bolting or by othermethods. In the embodiment depicted in FIG. 5, a plurality of fasteners520, a respective passed through holes 526, 524 formed through the guide222 and mounting pad 504 and engage a nut 522 to secure the lateralguide 222 to the mounting pad 504 of the spacer assembly 260.

[0041] The lateral guide 222 is typically fabricated from thermoplastic,stainless steel or ceramic similar to the outer edge supports 224A. Thelateral guide 222 has a body 530 that includes a bottom surface 534 anda face 534. The bottom surface 534 is disposed on the mounting pad 504,typically parallel to the upper surface 330 of the end effector 206. Theface 534 extends from the bottom surface 534 and is oriented parallel tothe datum line 220 and perpendicular to the plane of the end effector206 and substrate 116.

[0042] Referring additionally to FIG. 2, the face 534 is configured tointerface with the lateral edge 540 of the substrate 116 so that thesubstrate is laterally restrained between the faces 532 of lateralguides 222 disposed on opposing spacer assemblies 260. In one embodimentthe face 534 is substantially parallel to a plane defined by the datumline 220 and the centerline 218 of the transfer robot 104. The face 534may alternatively be angled into the body 530 from the bottom surface534 to facilitate entry of the substrate between the faces 534 ofopposing lateral guides 222.

[0043]FIG. 6 is an exploded view of another embodiment of a lateralguide 600 that may be utilized with the spacer assembly 260 in place ofthe lateral guide 222. The lateral guide 600 has a body 602 thatincludes a bottom surface 614 and a face 612.

[0044] The bottom surface 614 is disposed on the mounting pad 504,typically parallel to the upper surface 330 of the end effector 206. Aplurality of fasteners 520 are disposed through holes 610, 524 formedthrough the body 602 and mounting pad 504 and engage nuts 522 to securethe lateral guide 600 to the mounting pad 504.

[0045] The face 612 extends from the bottom surface 614 and is orientedparallel to the datum line 220 and perpendicular to the plane of the endeffector 206 and substrate 116. The face 612 includes a plurality ofsteps 604 facing the datum line 220. The steps 604 include a supportsurface 606 and a retaining surface 608. The support surface 606 isoriented parallel to the plane of the end effector 206 and datum line220 and is adapted to support the substrate thereon.

[0046] The retaining surface 608 extends upward from the support surface606 and is oriented parallel to the plane defined by the centerline 218(shown in FIG. 2) and datum line 220. The retaining surface 608 of theface 612 is configured to capture of the substrate 116 against anopposing face 612 of a lateral guide (not shown) disposed on theopposite side of the datum line 220 to prevent the substrate from movingduring substrate transfer.

[0047]FIG. 7 is a perspective view of another embodiment of a spacerassembly 700. The spacer assembly 700 includes an outrigger 702 and asubstrate support 730. The outrigger 702 has a first end 706 and asecond end 708 attached to a mounting pad 704. The outrigger 702 isconfigured to position the substrate support 730 to interface with acorner 710 of the substrate 116 thereby preventing the substrate 116from shifting on the end effector 206 while the substrate is moved bythe robot 104.

[0048] The substrate support 730 includes a generally “L” shaped body732 having a bottom surface 734, a first interior face 736 and a secondinterior face 738. The bottom surface 734 is disposed on the mountingpad 704. The first interior face 736 includes a plurality of steps 740.Each step 740 includes a support surface 742 and a retaining surface744. The support surface 742 is configured to support the substrate 116thereon and is typically oriented in a plane parallel to the mountingpad 704 and upper surface 330 of the end effector 206. The supportsurface 742 may also be textured, embossed, dimpled, slotted orotherwise include a plurality of surface features as discussed withreference to FIGS. 9A-F described further below.

[0049] The retaining surface 744 extends vertically relative to themounting pad 504. Alternatively, the retaining surface 744 may be flaredto provide an entrance angle that facilitates seating of the substrate116 on the support surface 742. The substrate 116 is laterally capturedon the end effector 206 between the retaining surface 744 and the outeredge support 224A (shown in FIG. 2) as the substrate is rotated aboutthe centerline 218 of the transfer robot 104.

[0050] The second interior face 738 is generally oriented parallel ofthe plane defined by the center and datum lines 218, 220, and is alsoperpendicular to the support and retaining surfaces 742, 744. The secondinterior face 738 may alternatively be flared to enhance entry of thesubstrate 116 between second interior faces disposed on opposing spacerassemblies 700. In another embodiment, the second interior face 738 mayinclude plurality of steps similar to the steps similar to thosedescribed with reference to the lateral guide 600 discussed above.

[0051] The first end 706 of the outrigger 702 is disposed in a channel510 formed in the end effector 206. The channel 510 includes a pluralityof slots 512 that accept fasteners 520 passing through holes 514 formedthrough the first end 706 of the outrigger 702. A nut 518 is mated witheach fastener 520 to secure the outrigger 702 to the end effector 306.The slots 512 are oriented substantially perpendicular to the datum line220 so that the position of the second face 738 of the substrate support730 may be adjusted to accommodate the width of the substrate 116 withina predefined tolerance without undue close part tolerances.

[0052] The substrate support 730 is coupled to the mounting pad 704 in amanner allowing adjustment in a direction parallel to the datum line220. In one embodiment, the mounting pad 704 includes a plurality slots724 having an orientation parallel to the datum line 220. A plurality offasteners 720 are disposed through a hole 722 formed through thesubstrate support 730 and pass through a respective one of the slots724. A nut 726 is threaded onto each fastener 720. The substrate support730 may be positioned relative to the mounting pad 704 as the fasteners720 may move laterally in the slots 724 to a predetermined positionalong a direction parallel to the datum line 220, the nut 726 istightened to secure the substrate support 730 to the mounting pad 704 ofthe spacer assembly 700.

[0053]FIG. 8 depicts one embodiment of the center support 226. Thecenter support 226 generally includes an annular body 802 havingmounting hole 804 disposed therethrough. The center support 226 isfabricated from materials similar to that utilized for the outer edgesupport 224A described above. The center support 226 has a supportsurface 806 typically utilized to support a center region of asubstrate.

[0054] A fastener 808 is disposed through a hole 812 defined through theend effector 206. The fastener 808 may be a screw, rivet, dowel pin,spring pin or other retaining device. In the embodiment depicted in FIG.8, the fastener 808 mates with a threaded nut 816 disposed on the lowersurface of the end effector 206. The lower surface of the end effector206 may include a recess 814 to allow the nut 816 and fastener 808 toremain flush or recessed from the exterior of the end effector 206. Thesupport surface 806 may be textured to minimize heat transfer betweenthe substrate 116 and center support 226.

[0055] FIGS. 9A-F depict various embodiments of a patterned supportsurface that minimizes contact area available for heat transfer with thesubstrate. By minimizing the contact area of the support surfaceavailable for heat transfer, the hot substrate will not heat the supportsurface as quickly as pads having a contact area comprising the entiretop surface. Although FIGS. 9A-F depict a few exemplary patterns forreducing the contact area between the support surface and substratesupported thereon, other patterns are contemplated and considered withinthe scope of the invention claimed below. Utilization of a patternedsupport surface is particularly advantageous when the support surface isfabricated from a polymer.

[0056]FIG. 9A depicts a perspective view of a patterned support surface902A. The support surface 902A comprises a plurality of dimples 904formed therein. The dimples 904 may have any geometric configuration andmay be disposed on the top surface 902A in a symmetrical, regular (i.e.,equally spaced) or random pattern. The dimples 904 extend below a planeof the support surface 902A that supports the substrate thereby reducingthe contact area of the support surface 902A with the substrate.

[0057] In the embodiment depicted in FIG. 9B, a patterned supportsurface 902B includes a plurality of protrusions 906 extending from thesupport surface 902B. The protrusions 906 may have any geometricconfiguration and may be disposed on the support surface 902B in asymmetrical, regular (i.e., equally spaced) or random pattern. Eachprotrusions 906 has a top 908 that lies on a common plane that supportsa substrate seated thereon. The top 908 may be flat as shown, curved orpointed. As the substrate is seated on the protrusions 906, the contactarea of the support surface 902B with the substrate is reduced.

[0058] In the embodiment depicted in FIG. 9C, a patterned supportsurface 902C includes a grid 910 extending from the support surface902C. The grid 910 generally comprises a web of projecting supportmembers 912 that may have any geometric configuration and may bedisposed on the support surface 902C in a symmetrical, regular (i.e.,equally spaced) or random pattern. The support member 912 generallyproject to a common plane that supports a substrate seated thereon anddefines a recessed area 914 therebetween. As the substrate is seated onthe support members 912 of the grid 910, the contact area of the supportsurface 902C is reduced.

[0059] In the embodiment depicted in FIG. 9D, a patterned supportsurface 902D includes a mesh 916 extending from the support surface902D. The mesh 916 generally comprises a plurality of intersectingridges 918 that project from the support surface 902D. The ridges 918may intersect and any angle and may be linear, curved or complex inform. The ridges 918 may be disposed on the support surface 902C in asymmetrical, regular (i.e., equally spaced) or random pattern. Theridges 918 generally project to a common plane that supports a substrateseated thereon and defines a recessed area 920 therebetween. As thesubstrate is seated on the ridges 918 of the mesh 916, the contact areaof the support surface 902D is reduced.

[0060] In the embodiment depicted in FIG. 9E, a patterned supportsurface 902E includes a plurality of ridges 922 extending from thesupport surface 902E. The ridges 922 generally project from the supportsurface 902E and may be linear, curved or complex in form. The ridges922 may be disposed on the support surface 902E in a symmetrical,regular (i.e., equally spaced) or random pattern. The ridges 922generally project to a common plane that supports a substrate seatedthereon and defines a recessed area 924 therebetween. As the substrateis seated on the ridges 922, the contact area of the support surface isreduced.

[0061] In the embodiment depicted in FIG. 9E, a patterned supportsurface 902F includes a plurality of grooves 926 form in the top surface902F. The grooves 926 generally project into the support surface 902Fand may interest, be linear, curved or complex in form. The grooves 926may be disposed on the support surface 902F in a symmetrical, regular(i.e., equally spaced) or random pattern. The grooves 926 reduce thesurface area of the support surface 902F that supports a substrateseated thereon, thereby reducing the contact area available for heattransfer.

[0062] Thus, the inventive substrate supports substantially reduce oreliminate pad material sticking to the substrate after repeated cycling.Reducing and eliminating contamination of the substrate by the substratesupports correspondingly increases device yield. Moreover, the inventiveedge supports capture the substrate therebetween to substantiallyeliminate substrate movement relative to the end effector duringsubstrate transfer. Additionally, using lateral guides that bound thesubstrate on the edges adjacent the edge supports further enhancesretaining the substrate on the end effector thereby allowing greaterrobot rotational speed that enhance substrate throughput.

[0063] While the foregoing is directed to embodiments of the presentinvention, other future embodiments of this invention may be revisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. An end effector assembly for supporting aquadrilateral substrate during substrate transfer, the end effectorassembly comprising: an end effector having a first end adapted forcoupling to a robot linkage and a distal end; a first inner edge supportdisposed on the first end of the end effector and having a face; and afirst outer edge support disposed on the distal end of the end effectorand having a face oriented parallel to and facing the face of the firstinner edge support.
 2. The end effector assembly of claim 1, wherein theouter edge support is fabricated from a thermoplastic material having amelting point greater than about 500 degrees Celsius and a Rockwell Mhardness less than about
 150. 3. The end effector assembly of claim 1,wherein the distal end of the end effector further comprises a pluralityof slots adapted for accepting fasteners disposed through the outer edgesupport.
 4. The end effector assembly of claim 3, wherein the slots areorientated perpendicular to the face of the outer edge support.
 5. Theend effector assembly of claim 1, wherein the face of the outer edgesupport further comprises: a plurality of steps.
 6. The end effectorassembly of claim 5, wherein each of the steps further comprises: avertical surface; and a patterned horizontal surface adapted to supportthe substrate.
 7. The end effector assembly of claim 1, wherein the endeffector further comprises: a base disposed at the first end and havinga datum line passing therethrough; a first member extending from oneside of the base to the distal end of the end effector; and a secondmember extending from an opposite side of the base to the distal end ofthe end effector and mirroring the first member about the datum line. 8.The end effector assembly of claim 7, wherein the first outer edgesupport is disposed on the distal end of the first member; and a secondouter edge support is disposed on the distal end of the second member.9. The end effector assembly of claim 7 further comprising: a secondouter edge support is disposed on the distal end of the second member;and a second inner edge support is disposed on the first end of the endeffector in a position relative to the first inner edge support mirrorabout the datum line.
 10. The end effector assembly of claim 9, whereinthe second outer edge support has a face coplanar with the face of thefirst outer edge support; and the second inner edge support has a facecoplanar with the face of the first inner edge support.
 11. The endeffector assembly of claim 1 further comprising: a first lateral guidecoupled to the end effector and having a face; and a second lateralguide coupled to the end effector and having a face oriented towards andparallel to a face of the first lateral guide, the faces of the firstlateral guide, the second lateral guide, the first inner edge supportand the first outer edge support defining a quadrilateral substrateretaining pocket.
 12. The end effector assembly of claim 1 furthercomprising: a first lateral guide coupled to the end effector and havinga face oriented perpendicular to the face of the first outer edgesupport.
 13. The end effector assembly of claim 12 further comprising:an outrigger having a first end coupled the end effector and a secondend coupled to the first lateral guide, wherein the second end of theoutrigger oriented outward of the first end relative to a datum linebisecting the end effector.
 14. The end effector assembly of claim 13,wherein the first lateral guide is adjustable in position relative tothe datum line.
 15. The end effector assembly of claim 16, wherein theat least one of the outrigger or the end effector further comprises aplurality of slots orientated substantially perpendicular to the datumline adapted for accepting a fastener coupling the outrigger and the endeffector.
 16. The end effector assembly of claim 12, wherein the face ofthe first lateral guide further comprises: a plurality of steps.
 17. Theend effector assembly of claim 1, wherein the first inner supportfurther comprises: a surface extending normally from an outer side ofthe face of the first inner support towards the first outer support. 18.The end effector assembly of claim 17, wherein the surface of the firstinner support further comprises: a plurality of steps.
 19. The endeffector assembly of claim 17 further comprising: an outrigger having afirst end coupled the end effector and a second end coupled to the firstinner support, wherein the second end of the outrigger oriented outwardof the first end relative to a datum line bisecting the end effector.20. The end effector assembly of claim 19, wherein the second end of theoutrigger is adjustable in a direction perpendicular to the datum line;and the first inner support is adjustable relative the outrigger in adirection parallel to the datum line.
 21. An end effector assembly forsupporting a substrate having a quadrilateral plane form duringtransfer, the end effector assembly comprising: a) an end effectorcomprising: a base; a first member extending from one side of the basemember to a distal end; and a second member extending from the oppositeside of the base member to a distal end, the first member and secondmember having a mirrored orientation relative to a datum line passingthrough the base; b) a first means for retaining a first edge of thesubstrate coupled to the distal end of the first member; c) a secondmeans for retaining the first edge of the substrate coupled to a distalend of the second member; d) a third means for retaining the second edgeof the substrate opposite the first edge coupled to the end effector;and e) a fourth means for retaining the second edge of the substratecoupled to the end effector.
 22. The end effector assembly of claim 21further comprising: f) a fifth means for retaining a third edge of thesubstrate disposed between the first and second edges, the first meanscoupled to the end effector.
 23. The end effector assembly of claim 22,wherein the fifth means for retaining a third edge is adjustablerelative to the datum line.
 24. The end effector assembly of claim 21,wherein each of the means further comprises: a plurality of steps, eachof the steps having a substrate support surface and a retaining surfaceextending upward from the substrate support surface, each retainingsurface oriented perpendicular to the datum line.
 25. The end effectorassembly of claim 24, wherein the retaining surface of the first meansis coplanar with the retaining surface of the second means.
 26. An endeffector assembly for supporting a substrate having a quadrilateralplane form during transfer, the end effector assembly comprising: a) anend effector comprising: a base; a first member extending from one sideof the base member to a distal end; and a second member extending fromthe opposite side of the base member to a distal end, the first memberand second member having a mirrored orientation relative to a datum linepassing through the base; b) a first outer edge support coupled to thedistal end of the first member and having a plurality of steps, each ofthe steps having a substrate support surface and a retaining surfaceextending upward from the substrate support surface, the retainingsurface oriented perpendicular to the datum line; c) a second outer edgesupport coupled to a distal end of the second member and having aplurality of steps, each of the steps having a substrate support surfaceand a retaining surface extending upward from the substrate supportsurface, the retaining surface coplanar with the retaining surface ofthe first outer edge support; d) a first inner edge support coupled tothe end effector and having a retaining surface facing an oppositedirection of the retaining surface of the second outer edge support; ande) a first inner edge support coupled to the end effector retainingsurface coplanar with the retaining surface of the first inner edgesupport.
 27. The end effector assembly of claim 26 further comprising: alateral guide coupled to the end effector and having a face orientedparallel to the datum line.
 28. The end effector assembly of claim 27further comprising: an outrigger having a first end coupled the endeffector and a second end coupled to the first lateral guide, whereinthe second end of the outrigger oriented outward of the first memberrelative to the datum line.
 29. The end effector assembly of claim 27,wherein the first lateral guide is adjustable in position relative tothe datum line.
 30. The end effector assembly of claim 28, wherein theat least one of the outrigger or the end effector further comprises aplurality of slots orientated substantially perpendicular to the datumline adapted for accepting a fastener coupling the outrigger and the endeffector.
 31. The end effector assembly of claim 27, wherein the face ofthe first lateral guide further comprises: a plurality of steps.
 32. Theend effector assembly of claim 26, wherein the first inner supportfurther comprises: a surface extending from an outer side of the face ofthe first inner support towards the first outer support and parallel tothe datum line.
 33. The end effector assembly of claim 32, wherein thesurface of the first inner support further comprises: a plurality ofsteps.
 34. The end effector assembly of claim 33 further comprising: anoutrigger having a first end coupled the end effector and a second endcoupled to the first inner support, wherein the second end of theoutrigger oriented outward of the first member relative to the datumline.
 35. The end effector assembly of claim 34, wherein the second endof the outrigger is adjustable in a direction perpendicular to the datumline; and the first inner support is adjustable relative the outriggerin a direction parallel to the datum line.
 36. The end effector assemblyof claim 26, wherein the outer edge support is fabricated from athermoplastic material having a melting point greater than about 500degrees Celsius and a Rockwell M hardness less than about
 150. 37. Theend effector assembly of claim 26, wherein the outer edge support isfabricated from at least one of stainless steel or ceramic.